Automatic brake for elevators



(No Model.)

J. H. BAIRD.

AUTOMATIC BRAKE FOR ELEVATORS.

No. 248,384. 1}atented Oct. 18,1881.

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ATTORNEYS.

NITED STATES PATENT OFFICE.

JOSEPH H. BAIRD, OF OAKVILLE, ASSIGNOR TO THE NAUGA'IUCK MACHINE COMPANY, OF UNION CITY, CONNECTICUT.

AUTOMATIC BRAKE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 248,384, dated October 18, 1881.

Application filed July 2, 1881.

To all whom it may concern:

Be it known that I, J OSEPH H. BAIRD, of Oakville, New Haven county, Connecticut, have invented a new and Improved Automatic Brake for Elevators and Hoisting-ll/Iaobines,

of which the following is a specification.

This invention is especially applicable to elevators andhoisting-machines, andits object is to prevent the rapid descent of the elevator [O in the event of the slipping or breaking of the driving-belt.

The invention consists of two pulleys, one fixed on the driving-shaft of the elevator, and the other on a parallel counter-shaft or stud,

I5 and a wedge held loosely in a socket with its point inserted between the pulleys and in contact with their faces, whereby a constant friction is created between said pulleys and wedge during the descent of the elevator.

Figure l is a plan of the device attached to an elevator. Fig. 2 is an end elevation of the same on line 00 00, Fig. 1.

Similar letters of reference indicate correspondin g parts.

In the drawings, A represents the stationary bed or housing of an elevator; B, the wormshaftjournaled thereon in boxes a a, and carrying on each end the fast and loose pulleys C D, E Frespeotiv'ely, said loose pulleys E F be- 0 ing held in place by collars G G on the ends of said shaft B.

H H represent the elevator-belts, and I I the shifting-bars, supported in carriers 1.

On the shaft B is keyed a pulley, K, and op- 3 5 posite it in the same plane is a pulley, L, keyed on a shaft, M, that is journaled in a box, b, on the elevator A. The faces of these pulleys K L are sufiiciently apart from each other to receive between them the brake-wedge N, that 40 is loosely supported in a vertical position in a socket, N, that is secured on the face of a standard, 0, projecting upward from the elevator bed or housing A.

A shaft, P, journaled in the elevator bed or housing A at right angles to the shaft B, is provided with a worm which meshes with the worm of the shaft B, and with cog-wheels c, which mesh with the racks (1, depending from (No model.)

the elevator, (not shown,) so that as the said shaft B is rotated, the elevator will be raised or lowered.

When the elevator is descending, the shaft B turns in the direction of the arrow, Fig. 2, and hence the revolving pulley K hearing against the beveled face, and the pulley L hearin g against the straight face of said wedge N, the said wedge N is drawn down between said pulleys K L with more or less force, according to their speed and the bevel of the said Wedge N, thereby creating sufficient frietion between the said pulleys K L to retard the revolutions of the shaft B, and consequently of the elevator. On the upward movement of the elevator the wedge N is released from the pressure of the pulleys K L,and hence offers 6 no obstacle to the free movement of said elevator.

It will be seen that this device is simple, automatic, and not so liable to get out of order.

Having thus described my invention, I claim as new and desire to secure by Letters Pateut 1. An improved automatic elevator-brake, constructed substantially as herein shown and described, consisting of two pulleys, one fixed on the elevator driving-shaft and the other fixed on a counter-shaft, and of a wedge held loosely and vertically with its point between the said pulleys and in contact with their faces, as set forth.

2. In an automatic elevator-brake, a vertically-moving wedge loosely held in a socket with its point between two pulleys, whereby the wedge is drawn between the said pulleys and sufficient friction created between them in the descent of the elevator to retard the same, substantially as shown and described.

3. In an automatic elevator-brake, the combination, with the pulleys K L and wedge N, of the supporting-socket N, substantially as 9:: and for the purpose described.

JOSEPH H. BAIRD.

Witnesses EDWARD F. COLE,

WM. R. WILLIAMS. 

